Study On Geometry Match Method Of Wheel And Rail Based On Dynamic Equivalent Conicity And Its Application

The wheel-rail matching state which could be assessed by equivalent conicity,is one of the key factors that affecting the stability of the vehicle.In the actual application environment,equivalent conicity could not only affected by wheel/rail profiles,but also has close relationship with track gauge.In view of the fact that the measured profile distortion points affect the wheel-rail matching calculation accuracy,the low-efficiency problem of traversal method when calculating dynamic equivalent conicity,the missing judgment of continuous multi-wave peak value method,and the problem that the traditional wheel-rail maintenance method cannot dynamically build relationship between wheel and the track.This paper studied measured profile smoothing method,the management recommended value,vehicle body periodically swaying evaluation method and wheel-rail maintenance decision method on basis of dynamic equivalent conicity.Five areas have been carried out in this paper:(1)Based on the characteristics of the measured wheel-rail profiles,combined with normal distance calculation,filtering,Boundary extension and reconstruction,the NFBR method is proposed and used to smooth the measured wheel-rail profiles.The multi-body dynamics software has been used to analyze and compare the contact point location before and after smoothing,the rolling radius difference curve and the equivalent conicity to verify the effectiveness of the NFBR method.The comparison result show that the method can well eliminate the distortion points and reduce the influence of the measurement error on the calculation result of the dynamic equivalent conicity.(2)Aiming at the calculation time bottleneck problem faced by the traversal algorithm in the dynamic equivalent conicity calculation process,a fast algorithm based on wheel-rail profile grading and interpolation algorithm is proposed.Numerical experiment shows that this method can reduce the calculation time by more than 90% compared with the traversal algorithm,and the calculation error of the fast method is less than 10%,which is more conducive to engineering applications.(3)The dynamic equivalent conicity distribution characteristics under different gauge conditions are studied from the statistical point of view.On the basis of a large number of measured results analysis,the recommended management values of the dynamic equivalent conicity for the LMB profile under different gauge conditions are proposed.The rationality of the proposed management value is verified by the multi-body dynamics simulations.(4)Aiming at the problem of missing judgment of the continuous 6-wave peaks over-limit method,the proportion of energy in the unstable frequency range to the total energy is taken into account in the periodic car-body swaying judgment,combined with the advantages of continuous multi-wave method,RMS and energy concentration rate,the continuous multi-wave vibration energy method is proposed and used to judge the car-body periodically swaying motion.On basis of the statistical analysis of a large number of car-body swaying sections,the thresholds of effective value and energy concentration rate of continuous multi-wave vibration energy method are given.The case study results show that the method can effectively identify the low-conicity periodically swaying motion.(5)Aiming at the limitation of the traditional maintenance decision-making,a wheel-rail integrated maintenance strategy based on dynamic equivalent conicity is proposed,which provides a quantitative decision-making basis for the cycle maintenance to state maintenance.The practicality and effectiveness of the strategy is verified by the case study of dynamic equivalent conicity.